Authorities kept all Los Angeles Unified School District campuses closed on Tuesday after a board member received an anonymous bomb threat, the Los Angeles Times reported. The Los Angeles School Police confirmed that the LAUSD shut down its institutes immediately, although it was unclear when the threat was made or to whom.

Further investigations are underway and citizens have been warned to stay away from the schools. TIME magazine reported that the police superintendent has called for every school in the district to be searched. "It is important that I take that precaution based on what has happened recently and what has happened in the past,” Ramon Cortines, the LAUSD superintendent, said at a press conference.